Feasibility of Natural Treatment and Recharge of Wastewater and Surface Waters Using Mined Phosphate Lands

The project involves the purification of reclaimed and excess surface waters by treatment through natural processes on lands previously mined by phosphate mining companies. As a result of the mining process, the phosphate companies produce open mine pits, clay settling areas (CSA) and tailing sand deposits, which the companies are required to reclaim as land and lakes, wetlands, pasture and agricultural lands. The basis for this project is the premise that the natural systems, in particular, wetlands created on CSAs followed by tailing sand filtration, will remove organic, inorganic and microbiological contaminants from the waters, resulting in water that will meet drinking water standards. The project envisions recharge to the underlying Floridan Aquifer, an extensive confined ground-water system, capable of storing and transmitting large quantities of water. The Florida Institute of Phosphate Research (FIPR) has funded the projects in support of this concept. Studies have been completed on the radiological and microorganism aspects of the percolation of water through tailing sand deposits. This feasibility study has identified five project sites where a total of 84 million gallons per day could be harvested, treated and recharged to the Floridan Aquifer at an average cost of less than $1.20 per 1,000 gallons. This approach fits well in the regional water resources management plan for the Southern Water Use Caution Area, which has projected need by the year 2020 of more than 300 million gallons per day (MGD) to meet agricultural, industrial and public water supply demands.